// 引用计数 优点

const user1 = {age:11};
const user2 = {age:111};
const user3 = {age:110};
const user4 = {age:115};
const nameList = [user1.age, user2.age,user3.age]
function fn(){
    const num1 = 1;// 执行完会被回收
    const num2 = 2;
}
fn()

function fn (){
    const obj1 = {}
    const obj2 = {}
    // 循环引用
    obj1.name = obj2// 还在互相引用
    obj2.name = obj1

    return 'hshs'
}

fn()